Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752302AbcDASbQ (ORCPT ); Fri, 1 Apr 2016 14:31:16 -0400 Received: from cmta7.telus.net ([209.171.16.80]:60660 "EHLO cmta7.telus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751022AbcDASbO convert rfc822-to-8bit (ORCPT ); Fri, 1 Apr 2016 14:31:14 -0400 X-Authority-Analysis: v=2.1 cv=daR9pije c=1 sm=2 tr=0 a=zJWegnE7BH9C0Gl4FFgQyA==:117 a=zJWegnE7BH9C0Gl4FFgQyA==:17 a=L9H7d07YOLsA:10 a=9cW_t1CCXrUA:10 a=s5jvgZ67dGcA:10 a=Pyq9K9CWowscuQLKlpiwfMBGOR0=:19 a=IkcTkHD0fZMA:10 a=fRZ0p0C6Dm7RbiL2e4UA:9 a=QEXdDO2ut3YA:10 X-Telus-Outbound-IP: 173.180.45.4 From: "Doug Smythies" To: "'Srinivas Pandruvada'" , "=?UTF-8?Q?'J=C3=B6rg_Otte'?=" , "'Rafael J. Wysocki'" Cc: "'Rafael J. Wysocki'" , "'Linux Kernel Mailing List'" , "'Linux PM list'" References: <2727017.UmaUvtBLeX@vostro.rjw.lan> <3623107.tlAuqH4F7s@vostro.rjw.lan> <1459532674.13525.136.camel@linux.intel.com> In-Reply-To: <1459532674.13525.136.camel@linux.intel.com> Subject: RE: [intel-pstate driver regression] processor frequency very high even if in idle Date: Fri, 1 Apr 2016 11:31:12 -0700 Message-ID: <003801d18c44$ab9134e0$02b39ea0$@net> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AdGMPh4FvA3Rz/ysQdaykw/CPUWJuwAAxZRQ Content-Language: en-ca Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1463 Lines: 35 On 2106.034.01 10:45 Srinivas Pandruvada wrote: > On Fri, 2016-04-01 at 16:06 +0200, Jörg Otte wrote: > > > > > > >> Done. Attached the tracer. >> For me it looks like the previous one of the failing case. > > The traces show that idle task is constantly running without sleep. No, they (at least the first one, I didn't look at the next one yet) show that CPUs 2 and 3 are spending around 99% of their time not in state C0. That the sample rate is ending up at ~10 Milliseconds, indicates some high frequency (>= 100Hz) events on those CPUs. Those events, apparently, take very little CPU time to complete, hence a load of about 1% on average. By the way, I can recreate the high sample rate with virtually no load on my system easy, but so far have been unable to get the high CPU frequencies observed by Jörg. I can get my system to about a target pstate of 20 where it should have remained at 16, but that is about it. > The driver is processing samples for idle task for every 10ms and > aperf/mperf are showing that we are always in turbo mode for idle task. That column pretty much always says "idle" (or swapper for my way of doing things). I have not found it to very useful as an indicator, and considerably more so since the utilization changes. > > Need to find out why idle task is not sleeping. I contend that is it. I don't have enough reverted data, but so far this seems very much like that bug report I referenced earlier. ... Doug